Persistence of vision is the phenomenon of the eye by which an afterimage is thought to persist for approximately one twenty-fifth of a second on the retina.
The vision of a human is not as simple as light registering on a medium, since the brain has to make sense of the visual data eyes provide and construct a coherent picture of reality. This is visual perception. The visual perception is the ability to interpret the surrounding environment by processing information that is contained in visible light, and for human, the information contained in visible light is visual data provided by eyes. The resulting perception is also known as eyesight, sight, or vision (and the terms can be attached with following adjectives: visual, optical, or ocular, e.g. optical vision).
Persistence of vision is widely used. And below list some usages.
In traditional TV, images are displayed in closely-timed sequence one after another. Viewers don't notice the fractional skips between images because that persistence of vision fills in the momentary gap to make the motion seem seamless.
In 3D system including a 3D display and shutter glasses, left and right images (or called views) are displayed sequentially and synchronized with the left eye glass and right eye glass, i.e. when left image is displayed, the left eye glass is set transparent by setting the shutter for left eye glass on and the right eye is set dark by setting the shutter for the right eye glass off. And the similar applies when the right image is displayed. When the display frequency (i.e. switching frequency of the shutter glasses) is high enough, e.g. 120 Hz or 240 Hz for both eyes, viewer can perceive 3D depth without feeling the flicker between left and right images.
Persistence of vision displays (POV display) composes an image by displaying one spatial portion of the image at a time in rapid succession (for example, one column of pixels every few milliseconds). A 2 dimensional POV display is often accomplished by means of rapidly moving a single row of LEDs along a linear or circular path. The effect is that the image is perceived as a whole by the viewer as long as the entire path is completed during the visual persistence time of the human eye. A further effect is often to give the illusion of the image floating in mid-air. A 3 dimensional POV display is often constructed using a 2D grid of LEDs which is swept or rotated through a volume. POV display devices can be used in combination with long camera exposures to produce light writing.
The present invention provides a method to display an image larger than the size of the display to the viewer.